ATLANTA, Georgia (CNN) -- If you or a loved one develops pneumonia or has a heart attack and is taken to a hospital, do you know what the chances are of getting out alive?

Hospital death rates are difficult to pin down because some see sicker patient populations than others.

Your chances of survival have become a little easier to find, thanks to information included in the government's Hospital Compare Web site.

For the first time, death rates during the past two years from pneumonia are included with death rates from heart attack and heart failure for individual hospitals across the country. These numbers can be compared with the national mortality rate for heart attack (16.1 percent), heart failure (11.1 percent) and pneumonia (11.4 percent).

In the past, the information specified only whether a hospital was performing at, above or below the national average, without disclosing numbers.

But some question the worth of these mortality rates for the general public.

Hospital Compare is run by the Centers for Medicare and Medicaid Services, an agency of the U.S. Department of Health and Human Services.

In addition to the pneumonia mortality rates, the Web site recently added statistics on the quality of hospital care received by children. The new data join information on process of care, patient satisfaction and patient experience.

The site, launched in 2005, is designed to benefit both patients and hospitals.

"CMS' goal for updating and enhancing the Hospital Compare Web site is to provide usable and accurate information about hospital performance to providers and communities that will encourage hospitals to excel in the quality of care they provide," said Kerry Weems, acting administrator of the Centers for Medicare and Medicaid Services, said in a statement Wednesday.

Don't Miss

"With these new enhancements, consumers and health care providers will be able to look at individual hospital mortality scores. We hope that this new information will cement the Web site's role as a key driver in improving the quality and reliability of care in the nation's hospitals."

Hospital death rates have always been a slippery number to pin down because some hospitals see patient populations who are sicker or have more risk factors than other hospitals. The new mortality outcome measures are "risk-adjusted," meaning they take into account the previous health condition of patients.

Rich Umbdenstock, president and CEO the American Hospital Association, welcomes the information.

"People in the general public look at mortality or survival rate as being a very key indicator," Umbdenstock said. "And [pneumonia, heart attack and heart failure] are three areas in which we have national agreement in how to define, measure and report outcomes."

Umbdenstock says that this kind of information will help consumers make health care decisions and help hospitals zero in on where to improve.

"It's great to know how you are doing. You need to know how you're doing so you can do better," he said.

Others agree that it will help hospitals do a better job, but the question how much it will help the individual patient.

"In the short run, it will allow the hospital to look more carefully at their own data and improve things, but for individual patients who want to choose their own care, it can be more misleading than helpful," said Jeffrey Kirsch, chairman of anesthesiology at Oregon Health and Science University and chairman of the university's professional board.

But Kirsch believes that making certain information available to the public is a step in the right direction.

"It is a good way to get the process going, but it is not enough and not the right type of information," he said. He added that "we are still in the early stages of this process."

Health Library

Robert Kaplan, the Wasserman chairman of the Department of Health Services in the School of Public Health at the University of California, Los Angeles, agrees.

"It is a bit hard to digest for the average consumer," he said. A methodological problem is that various things are done to adjust for risk, he added, but no adjustment is perfect.

Kaplan said that some of the other indicators in Hospital Compare, beyond mortality rates, may be of interest to the patient, especially those that relate to the quality of a patient's experience.

Even one of the collaborators on the database says the measures are more for hospitals than for individuals.

"We have been working with CMS for five or six years to come up with measures that people could trust," said Harlan Krumholz, a cardiologist and professor of medicine and epidemiology and public health at Yale University. "But one thing that is true is that no one sees this measure as a means to select hospital when critically ill.

"We think that putting this information out and clearly communicating it to hospitals and their boards means that people have to look at their performance. It is a tool to understand how you are doing," he said.

Krumholz believes that good will trickle down to consumers.

"I do hope that it empowers groups of patients and community groups and hospital boards to engage in a conversation with their institution. They really need to be held accountable," he said. "This is a tool that can improve the conversation."